The present invention relates to airbag inflation control systems and methods and more particularly, to inflation control systems and methods including multiple crash sensors, each of which affects the accumulation of gas in an airbag.
Frontal impacts were the number one killer of vehicle occupants in automobile accidents with about 16,000 fatalities each year. Side impacts were the second cause of automobile related deaths with about 8,000 fatalities each year. The number of fatalities in frontal impacts as well as side impacts has been decreasing due to the introduction of airbags and mandatory seatbelt use laws.
Several automobile manufacturers are now using side impact airbags to attempt to reduce the number of people killed or injured in side impacts. The side impact problem is considerably more difficult to solve in this way than the frontal impact problem due to the lack of space between the occupant and the side door and to the significant intrusion of the side door into the passenger compartment which typically accompanies a side impact.
Some understanding of the severity of the side impact problem can be obtained by a comparison with frontal impacts. In the Federal Motor Vehicle Safety Standard (FMVSS) 208 49 kph crash test which applies to frontal impacts, the driver, if unrestrained, will impact the steering wheel at about 30 kph. With an airbag and a typical energy absorbing steering column, there is about 40 cm to about 50 cm of combined deflection of the airbag and steering column to absorb this 30 kph difference in relative velocity between the driver and vehicle interior. Also, there is usually little intrusion into the passenger compartment to reduce this available space.
In the FMVSS 214 standard crash for side impacts, the occupant, whether restrained or not, is impacted by the intruding vehicle door also at about 30 kph. In this case there is only about 10 to 15 cm of space available for an airbag to absorb the relative velocity between the occupant and the vehicle interior. In addition, the human body is more vulnerable to side impacts than frontal impacts and there is usually significant intrusion into the passenger compartment. A more detailed discussion of side impacts can be found in a paper by Breed et al, xe2x80x9cSensing Side Impactsxe2x80x9d, Society of Automotive Engineers Paper No. 940651, 1994, which is incorporated by reference herein.
Ideally, an airbag for side impact protection would displace the occupant away from the intruding vehicle door in an accident and create the required space for a sufficiently large airbag. Sensors used for side impact airbags, however, usually begin sensing the crash only at the beginning of the impact at which time there is insufficient time remaining to move the occupant before he is impacted by the intruding door. Even if the airbag were inflated instantaneously, it is still not possible to move the occupant to create the desired space without causing serious injury to the occupant. The problem is that the sensor that starts sensing the crash when the impact has begun, is already too late, i.e., once the sensor detects the crash, it is usually too late to properly inflate the airbag.
There has been discussion over the years in the vehicular safety community about the use of anticipatory sensors so that the side impact accident could be sensed before it occurs. Prior to 1994, this was not practical due to the inability to predict the severity of the accident prior to the impact. A heavy truck, for example, or a tree is a much more severe accident at low velocity than a light vehicle or motorcycle at high velocity. Further, it was not possible to differentiate between these different accidents with a high degree of certainty.
Once a sufficiently large airbag is deployed in a side impact and the driver displaced away from the door and the steering wheel, he will no longer be able to control the vehicle that could in itself cause a serious accident. It is critically important, therefore, that such an airbag not be deployed unless there is great certainty that the driver would otherwise be seriously injured or killed by the side impact. Anticipatory sensors have heretofore not been used because of their inability to predict the severity of the accident. As discussed more filly below, the present invention solves this problem and therefore makes anticipatory sensing practical. This permits side impact airbag systems that can save a significant percentage of the people who would otherwise be killed as well as significantly reducing the number and severity of injuries. This is accomplished through the use of pattern recognition technologies such as neural networks such as discussed in U.S. Pat. No. 5,829,782, incorporated by reference herein.
Neural networks are capable of pattern recognition with a speed, accuracy and efficiency heretofore not possible. It is now possible, for example, to recognize that the front of a truck or another car is about to impact the side of a vehicle when it is one to three meters or more away. This totally changes the side impact strategy since there is now time to inflate a large airbag and push the occupant out of the way of the soon to be intruding vehicle. Naturally, not all side impacts are of sufficient severity to warrant this action and therefore, there will usually be a dual inflation system as described in more detail below.
Although the main application for anticipatory sensors is in side impacts, frontal impact anticipatory sensors can also be used to identify the impacting object before the crash occurs. Prior to going to a full frontal impact anticipatory sensor system, neural networks can be used to detect many frontal impacts using data in addition to the output of the normal crash sensing accelerometer. Simple radar or acoustic imaging, for example, can be added to current accelerometer based systems to give substantially more information about the crash and the impacting object than possible from the acceleration signal alone.
The side impact anticipatory sensor of this invention can use any of a variety of technologies including optical, radar, acoustical, infrared or a combination of these. The sensor system typically contains a neural network processor to make the discrimination however a simulated neural network, a fuzzy logic or other algorithm operating on a microprocessor can also be used.
With respect to prior art related to the subject matter of this application, reference is made to European Patent Publication No. 0 210 079 (Davis). Davis describes, inter alia, a radar system for use in connection with an airbag deployment apparatus to prevent injury to passengers when impact with an approaching object is imminent. Voltage level inputs representative of the distance between an object and the vehicle, the approach rate of the object with respect to the vehicle, the vehicle speed and driving monitor inputs, e.g., steering angles, turning rates and acceleration/deceleration, are all generated by appropriate detectors, weighted according to their importance to a normal vehicle operators"" sensed safe or danger levels and then the weighted input voltages are summed to provide an xe2x80x9cinstantaneous voltage levelxe2x80x9d. This instantaneous voltage level is compared with a predetermined voltage level and if the instantaneous voltage level falls within a predetermined safe zone, output signals are not produced. On the other hand, if the instantaneous voltage level falls outside of the safe zone, i.e., within a danger zone, then the system can be designed to initiate deployment of the airbag on the additional condition that the vehicle speed is above a predetermined level. For example, the system can be programmed to deploy the airbag when the vehicle speed is between 35 and 204 miles per hour at a time of about 0.2 second prior to impact thereby enabling the airbag sufficient time to fully inflate.
As far as structure, Davis includes a radar system that includes an antenna assembly, a signal-processing unit and an output monitor. Davis relies on a radar signal generated by an antenna in the antenna assembly and which causes a return signal to be produced upon reflection of the radar signal against the approaching object. The return signal is received by a transceiver to be processed further in order to determine the distance between the object and the vehicle and the rate the object is approaching the vehicle. The return signal from the radar signal generated by the antenna is a single pulse, i.e., a single pixel. The elapsed time between the emission of the radar signal by the antenna and the receipt of the return signal by the transceiver determines the distance between the object and the vehicle and based on the elapsed time for a series of radar signals generated at set intervals, it is possible to determine the approach rate of the object relative to the vehicle.
In operation, the approach rate of the object relative to the vehicle, the distance between the object and the vehicle, the vehicle speed as well as other driving parameters are converted to voltage levels. Davis then uses an algorithm to weigh the voltage levels and compare the voltage levels to predetermined conditions for which airbag deployment is desired. If the conditions are satisfied by the results of the algorithm operating on the weighted voltage levels, then the airbag is deployed. In one embodiment, by appropriate manipulation of the voltage levels, false-triggering of the airbag can be prevented for impacts with objects smaller than a motorcycle, i.e., the voltage corresponding to a motorcycle at a certain distance from the vehicle is smaller than the voltage corresponding to a truck, for example at that same distance.
Davis does not attempt to recognize any pattern of reflected waves, i.e., a pattern formed from a plurality of waves received over a set period of time, from many pixels simultaneously (light and CCDs) or of the time series of ultrasonic waves. A tree, for example can have a smaller radar reflection (lower voltage in Davis) than a motorcycle but would have a different reflected pattern of waves (as detected in the present invention). Thus, in contrast to the inventions described herein, Davis does not identify the object exterior of the vehicle based on a received pattern of waves unique to that object, i.e., each different object will provide a distinct pattern of reflected or generated waves. The radar system of Davis is incapable of processing a pattern of waves, i.e., a plurality of waves received over a period of time, and based on such pattern, identify the object exterior of the vehicle. Rather, Davis can only differentiate objects based on the intensity of the signal.
International Publication No. WO 86/05149 (Karr et al.) describes a device to protect passengers in case of a frontal or rear collision. The device includes a measurement device mounted in connection with the vehicle to measure the distance or speed of the vehicle in relation to an object moving into the range of the vehicle, e.g., another vehicle or an obstacle. In the event that prescribed values for the distance and/or relative speed are not met or exceeded, i.e., which is representative of a forthcoming crash, a control switch activates the protection and warning system in the vehicle so that by the time the crash occurs, the protection and warning system has developed its full protective effect. Karr et al. is limited to frontal crashes and rear crashes and does not appear to even remotely relate to side impacts. Thus, Karr et al. only shows the broad concept of anticipatory sensing in conjunction with frontal and rear crashes.
U.S. Pat. No. 4,966,388 (Warner et al.) relates to an inflatable system for side impact crash protection. The system includes a folded, inflatable airbag mounted within a door of the vehicle, an impact sensor also mounted within the door and an inflator coupled to the impact sensor and in flow communication with the airbag so that upon activation of the inflator by the impact sensor during a crash, the airbag is inflated.
U.S. Pat. No. 3,741,584 (Arai) shows a pressurized air container and two air lines leading to a protective air bag. An air line passes through a first valve which is controlled by an anticipatory sensor and the other air line passes through a second valve controlled by an impact detector. The purpose of having two sensors associated with different valves is to ensure that the protective bag will inflate even if one of the crash sensors does not operate properly.
U.S. Pat. No. 3,861,710 (Okubo) shows an airbag inflation system with a single airbag which is partially inflated based on a signal from an obstacle detecting sensor and then fully inflated based on a signal from an impact detecting sensor. The obstacle detecting sensor controls release of gas from a first gas supply source into the gas bag whereas the impact detecting sensor controls release of gas from a second gas supply source into the gas bag. The first gas supply source includes a first gas container filled with a proper volume of gas for inflating the gas bag to a semi-expanded condition, a first valve mechanism, a pipe between the first gas container and the first valve mechanism and a pipe between the first valve mechanism and the gas bag. The second gas supply source includes a second gas container filled with gas in a volume supplementing the volume of gas in the first gas container so that the contents of both gas containers will fully inflate the gas bag, a second valve mechanism, a pipe between the second gas container and the second valve mechanism and a pipe between the first valve mechanism and the gas bag.
U.S. Pat. No. 3,874,695 (Abe et al.) shows an inflating arrangement including two inertia-responsive switches and coupled gas-generators. The gas-generators are triggered by the switches to inflate an airbag. The switches are both crash sensors and measured acceleration produced during the collision, and thus are not anticipatory sensors. The purpose of the two switches operative to trigger respective gas-generators is to enable the airbag to be inflated to different degrees. For example, if the crash involving the vehicle is a low speed crash, then only switch is actuated and gas-generated is triggered and the airbag will be inflated to part of its full capacity.
In U.S. Pat. No. 5,667,246 (Scholz et al.), there are two accelerometers, each of which provides a signal when the value of the increase in deceleration exceeds a respective threshold value. The signal from accelerometer is set to a first ignition stage and through a delay member to a second ignition stage. The second ignition stage also receives as input, a signal from the accelerometer and provides an inflation signal only when it receives a signal from both accelerometers. In operation, when the accelerometer sends a signal it serves to partially inflate the airbag while full inflation of the airbag is obtained only by input from both accelerometers.
Taniguchi (JP 4-293641) describes an apparatus for detecting a body moving around another body, such as to detect a car thief moving around a car. The apparatus includes a detection section supported on a support toll to the roof of the car. Taniguchi states that the detection section may be based on an infrared, microwave or ultrasonic sensor.
The invention comprises an anticipatory crash sensor arrangement which provides information about an object such as a vehicle about to impact the resident vehicle, i.e., the vehicle in which the anticipatory crash sensor arrangement is situated, and causes inflation of one or more airbags. Another crash sensor arrangement is also resident on the vehicle and provides information about the impact which is used to adjust the pressure in the airbag based on the information about the impact. Adjustment of the pressure may entail increasing the pressure in the airbag by, directing additional gas into the airbag(s), or releasing a control amount and/or flow of gas from the airbag(s).
More particularly, this invention comprises an anticipatory sensor system which uses (i) a source of radiant energy either originating from or reflected off of an object or vehicle which is about to impact the side of a target vehicle, plus (ii) pattern recognition means to analyze the radiant energy coming from the soon-to-be impacting object or vehicle to (iii) assess the probable severity of a pending accident and (iv) if appropriate, inflate an airbag prior to the impact so as to displace the occupant away from the path of the impacting object or vehicle to create space required to cushion the occupant from an impact with the vehicle interior. Although the primary area of application of this invention is for protection in side impacts, the invention also provides added protection in frontal impacts by reducing the incidence of injury to out-of-position occupants by permitting a slower inflation of the airbag and displacing the occupant away from the airbag prior to the impact.
Principal objects and advantages of this invention are:
1. To provide for the enhanced protection of occupants in side impacts by determining the probable severity of a pending accident and inflating an airbag prior to the impact to displace the occupant away from the vehicle door.
2. To provide for a method of identifying and classifying an object which is about to impact a vehicle.
3. To adapt pattern recognition techniques, and particularly neural networks, to permit the identification of objects external to an automotive vehicle and the determination of their approach speed and angle of potential collision.
4. To provide a method for assessing the probable severity of a pending accident based on the identification of the class of an object which is about to impact the vehicle plus stored information about the class of such objects such as its mass, strength and attachment to the earth.
5. To provide a method using an ultrasonic system for use in illuminating an object which is about to impact a vehicle and using the reflection of the ultrasonic illumination in combination with a pattern recognition system to identify the object.
6. To determine the approach velocity of an object which is about to impact a vehicle.
7. To identify that a truck is about to impact a vehicle.
8. To identify that an automobile is about to impact a vehicle.
9. To identify that a vehicle is about to impact with a tree.
10. To provide a method using an electromagnetic wave system for use in illuminating an object which is about to impact a vehicle and using the reflection of the electromagnetic wave illumination in combination with a pattern recognition system to identify the object.
11. To provide a method using an the passive infrared electromagnetic waves radiating from an object such as a motor vehicle in combination with a pattern recognition system to identify the object.
12. To provide a system for identifying an object which is about to impact a vehicle in a substantially side Impact.
13. To provide a system for identifying an object which is about to impact a vehicle in a substantially frontal impact.
14. To provide a system comprising a variable inflation airbag system where the control of the inflation of the airbag is determined by a prediction of the probable severity of an accident prior to the accident occurring.
15. To provide apparatus for inducing slack into a seatbelt in the event of a side impact to permit the occupant to be displaced sideways in the vehicle.
16. To provide for a single airbag module for protection of the head and torso of an occupant in side impacts.
17. To provide a single airbag module for mounting in the seat back of a vehicle for the protection of the head and torso of an occupant in side impacts.
18. To provide a structure and method for moving the occupant and his seat in the event of a side impact accident to increase the space between the occupant and the intruding object.
19. To provide for an airbag to be deployed external to the vehicle in conjunction with an anticipatory sensor in side impacts.
20. To provide a method using an ultrasonic wave system for use in illuminating an object which is about to impact a vehicle and using the reflection of the ultrasonic wave illumination in combination with a pattern recognition system to identify the object.
21. To provide a new and improved system and method for inflating an airbag based on information obtained by an anticipatory sensor and one or more additional crash sensors which provide information about the crash after the crash has begun and adjust the pressure in the airbag, if necessary.
To achieve some of these objects, an inflator system for inflating an airbag in accordance with the invention comprises gas inflow means for inflating the airbag with gas, vent means for controlling removal of gas from the airbag, a first anticipatory crash sensor for determining that a crash requiring deployment of the airbag will occur based on data obtained prior to the crash and, upon the making of such a determination, directing the gas inflow means to inflate the airbag, and a second crash sensor for determining that a crash requiring deployment of the airbag will occur or is occurring and, upon the making of such a determination, controlling the vent means to enable the removal of gas from the airbag whereby the pressure in the airbag is changed by the removal of gas therefrom enabled by the vent means.
The gas inflow means may be in the form of an inflator which is activated to produce gas and release the gas through conduits into the interior of the airbag. The gas inflow means can also be in the form of a tank of pressurized gas and a valve in a conduit leading from the tank to the interior of the airbag whereby opening of the valve causes flow of gas from the tank into the airbag. Any other type of structure or method which serves to cause accumulation of gas in the interior of the airbag can also be used as gas inflow means in accordance with the invention. The gas inflow means can also constitute multiple inflators which are independently activated based on, the severity of the anticipated crash. In this case, one inflator would be activated for a minor or average crash whereas for a more severe crash, two or more inflators would be activated thereby increasing the flow of gas into the airbag and the inflation rate and/or pressure therein. Each inflator could be controlled by the same or a different crash sensor.
The vent means may be in the form of a variable outflow port or vent integral with the airbag, e.g., a flap built in an exterior surface of the airbag and providing a regulatable conduit between the interior of the airbag and exterior of the airbag (regulatable both with respect to the amount of gas flowing therethrough and/or the rate of gas flowing therethrough). The vent means may also be in the form of a conduit leading from the interior of the airbag to the exterior of the airbag and having a regulatable valve in the conduit whereby regulated opening of the valve causes removal of gas from the interior of the airbag.
The airbag may be a side airbag arranged to inflate between the occupant and the side door. In this case, it is beneficial to provide some form of occupant displacement permitting means arranged in connection with the seat for permitting the occupant to be displaced away from the side door upon inflation of the airbag and thereby increase the space between the occupant and the side door. Such occupant displacement permitting means may be in the form of some structure which introduces slack into the seatbelt in conjunction with the deployment of the airbag or a mechanism by which the seat can be moved or is actually moved away from the side door, e.g., tilted inward.
The airbag can also be arranged to inflate to protect a rear-seated occupant and to this end, would be arranged in a back portion of the seat, attached to the back portion of the seat and/or integral with said back portion of the seat.
For any positioning and use, the airbag can be arranged in a housing of an airbag module. The airbag module could extend substantially along a vertical length of the back portion of the seat for a side airbag.
Another embodiment of the inflator system comprises inflator means for releasing a gas into the at least one airbag, a first anticipatory crash sensor for determining that a crash requiring deployment of the airbag will occur based on data obtained prior to the crash and, upon the making of such a determination, triggering the inflator means to release gas into the airbag, and a second crash sensor for determining that a crash requiring deployment of the airbag will occur or is occurring and, upon the making of such a determination, changing the rate at which gas accumulates in the airbag. To this end, the second crash sensor is structured and arranged to control outflow of gas from the airbag. Outflow of gas from the airbag may be controlled via a variable outflow port.
A method for inflating an airbag comprises the steps of making a first determination by means of an anticipatory crash sensor that a crash requiring deployment of the airbag will occur based on data obtained prior to the crash and, upon the making of such a determination, inflating the airbag, and making a second, separate determination by means of a second crash sensor that a crash requiring deployment of the airbag will occur or is occurring and, upon the making of such a determination, changing the rate at which gas accumulates in the airbag. The rate at which gas accumulates in the airbag may be changed by enabling and regulating outflow of gas from the airbag.
Preferred embodiments of the invention are described below and unless specifically noted, it is the applicant""s intention that the words and phrases in the specification and claims be given the ordinary and accustomed meaning to those of ordinary skill in the applicable art(s). If the applicant intends any other meaning, he will specifically state he is applying a special meaning to a word or phrase.
Likewise, applicant""s use of the word xe2x80x9cfunctionxe2x80x9d here is not intended to indicate that the applicant seeks to invoke the special provisions of 35 U.S.C. xc2xa7112, sixth paragraph, to define his invention. To the contrary, if applicant wishes to invoke the provisions of 35 U.S.C. xc2xa7112, sixth paragraph, to define his invention, he will specifically set forth in the claims the phrases xe2x80x9cmeans forxe2x80x9d or xe2x80x9cstep forxe2x80x9d and a function, without also reciting in that phrase any structure, material or act in support of the function. Moreover, even if applicant invokes the provisions of 35 U.S.C. xc2xa7112, sixth paragraph, to define his invention, it is the applicant""s intention that his inventions not be limited to the specific structure, material or acts that are described in the preferred embodiments herein. Rather, if applicant claims his inventions by specifically invoking the provisions of 35 U.S.C. xc2xa7112, sixth paragraph, it is nonetheless his intention to cover and include any and all structure, materials or acts that perform the claimed function, along with any and all known or later developed equivalent structures, materials or acts for performing the claimed function.
Throughout the description herein, the term xe2x80x9capproachingxe2x80x9d when used as an object or vehicle approaching another will mean the relative motion of the object toward the vehicle having the anticipatory sensor system. Thus, in a side impact with a tree, the tree will be considered as approaching the side of the vehicle and impacting the vehicle. In other words, the coordinate system used in general will be a coordinate system residing in the target vehicle. The xe2x80x9ctargetxe2x80x9d vehicle is the vehicle that is being impacted. This convention permits a general description to cover all of the cases such as where (i) a moving vehicle impacts into the side of a stationary vehicle, (ii) where both vehicles are moving when they impact, or (iii) where a vehicle is moving sideways into a stationary vehicle, tree or wall.
xe2x80x9cPattern recognitionxe2x80x9d as used herein will generally mean any system which processes a signal that is generated by an object, or is modified by interacting with an object, in order to determine which one of a set of classes that the object belongs to. Such a system might determine only that the object is or is not a member of one specified class, or it might attempt to assign the object to one of a larger set of specified classes, or find that it is not a member of any of the classes in the set. Each class can include a single object or a single type of objects. The signals processed are generally electrical signals coming from transducers which are sensitive to either acoustic or electromagnetic radiation and, if electromagnetic, they can be either visible light, infrared, ultraviolet, radar or low frequency radiation as used in capacitive sensing systems.
A trainable or a trained pattern recognition system as used herein means a pattern recognition system which is taught various patterns by subjecting the system to a variety of examples. The most successful such system is the neural network. Not all pattern recognition systems are trained systems and not all trained systems are neural networks. Other pattern recognition systems are based on fuzzy logic, sensor fusion, Kalman filters, correlation as well as linear and non-linear regression. Still other pattern recognition systems are hybrids of more than one system such as neural-fuzzy systems.
xe2x80x9cTo identifyxe2x80x9d as used herein will mean to determine that the object belongs to a particular set or class. The class may be one containing all trucks of a certain size or weight, one containing all trees, or all walls. In the case where a particular vehicle type is to be recognized, the set or class will contain only a single element, the particular vehicle type to be recognized.